Have you ever looked closely at a snail shell?
The shell can be many colors, but it is usually opaque.
When I downloaded this photo, I was surprised to see the channels on the inside of the shell. Can you see the vein-like, branching structures I'm talking about?
Let's zoom in:
It turns out that in young land snails like this one -- with a thinner, more transparent shell -- it is possible to see the interior vessels of the mantle and mantle cavity (lung).
In fact, if you look closely you might see some of the other internal organs, as well.
Do you like snails? See our previous post about snails:
Snail Q and A and fiction picture book, Escargot